Silicon wafers are the building blocks of a wide variety of semiconductor devices, such as solar cells, integrated circuits, and MEMS devices. For example, Evergreen Solar, Inc. of Marlboro, Mass. forms solar cells from silicon wafers fabricated by means of the well known “ribbon pulling” technique.
The ribbon pulling technique generally uses a specialized furnace that surrounds a crucible containing molten silicon and a growing ribbon crystal. The base of the furnace is typically formed from a solid, insulating material. Over time, this insulating material may become contaminated with the molten silicon splashing on it, or become damaged in some way, e.g., pieces of the material flaking off and falling into the melt. Unfortunately, this insulating material is typically expensive to replace and may cause undue downtime to repair or replace.